CODEWITHSUNDEEP
c++opencvunsigned-integeropencv-mat
SemtexB
SemtexB

Reputation: 660

OpenCV Mat::zeros not filled with 0

I have this code:

Mat Marker = Mat::zeros(MarkerSize, MarkerSize, CV_8UC1);

cout << "Marker:" << endl;
for (int row=0; row<MarkerSize; row++)
{
for (int col=0; col<MarkerSize; col++)
cout << Marker.at<int>(row, col)<<", ";

cout << endl;
}

where MarkerSize=6 and CV_8UC1 is preferably not changeable (for solution).

But I get this output:

Marker:
0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 65536, -1664876544, 
0, 0, 0, 1, 1141152964, 289879, 
0, 65536, -1664876544, 1817658372, 1531445252, 2147447774,

How come and how can I fix it?

Upvotes: 1

Views: 1280

Answers (1)

juanchopanza
juanchopanza

Reputation: 227418

Your Mat object is instantiated with CV_8UC1, that is, containing MarkerSize*MarkerSize 8 bit unsigned elements. But you iterate over it as if it container ints, going out of bounds in the iteration. For example, by accessing the elements with

Marker.at<uint8_t>(row, col)

Note that to print this you may have to cast to a different integer type, because uint8_t could be interpreted by std::cout as a char. For example

cout << static_cast<int>(Marker.at<uint8_t>(row, col)) <<", ";

Upvotes: 4

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